Tornado outbreak of May 19-22, 2017
the Tornado outbreak of May 19-22, 2017 'was a significant tornado outbreak that primarily effected the Great Plains and Ohio River Valley regions of the United States in mid to late May of 2017. The outbreak produced the strongest tornado of 2017, the 2017 Mulberry-Kokomo-Bluffton, Indiana tornado. This tornado peaked as a near-EF5 tornado as it moved over the major city of Kokomo, Indiana, and was the deadliest tornado of the season. It also produced the costliest tornado on record, the 2017 Bloomington, Indiana tornado, a tornado which destroyed nearly 20% of houses in Bloomington and devastated the IU campus there as a high-end EF3 tornado. Meteorological history Days prior to outbreak In early May, models began picking up on the possibility of a strong storm system tracking across the United States later that month, enhanced by a moist atmosphere. By May 7, models were suggesting some severe thunderstorms on May 18 and 19, and the following day the SPC highlighted a 15% Day 8 severe risk for portions of Colorado and New Mexico, concerning primarily damaging winds, some of which may gust to 75 mph. The following day, a 30% Day 8 severe risk was highlighted valid May 19, concerning the possibility of both damaging winds and tornadoes along a line from Dallas, Texas to Lincoln, Nebraska. The event further escalated on May 15, with a Day 3 Slight Risk, Day 4 30%, Day 5 15% and Day 6 30% now in place. A small severe weather outbreak occurred on May 18 along a line from Albuquerque, New Mexico, northeast to Denver, Colorado, however that event ultimately failed to produce any tornadoes, besides a single EF0 tornado near the Colorado-New Mexico state line. May 19 On the morning of May 19, a very unstable atmosphere was existent across the panhandles of Texas and Oklahoma, as well as into Kansas and Nebraska. The warm sector extended all the way to right along the North-South Dakota state line, but a more stable atmosphere existed here. With temperatures reaching 65-80°F (20-25°C) across the region, and strong wind shear in the atmosphere, as well as dew points nearing 65°F, the one thing that was expected to block the outbreak from becoming too large was the presence of a squall line that morning. The Storm Prediction Center issued a moderate risk of severe thunderstorms along a line from Amarillo, Texas to Colby, Kansas, including almost the entire panhandle of Oklahoma that morning. They were originally considering a high risk, however determined that predictability was too low for a high risk. However, despite this, several discrete supercells appeared, and a PDS tornado watch was issued at 1728 for most of the watch area, and with a dry line in place, the first tornado warnings of the outbreak were issued at just before 1800 across portions of New Mexico. The first tornado of the outbreak touched down at 1810 just west of Tatum, New Mexico, and was rated a EF4, the only F4/EF4 on record in the state, as well as the first of two violent tornadoes that day. 10 people were killed in this tornado, making it one of the deadliest, if not the deadliest, tornado in New Mexico state history. In the end, 42 tornadoes touched down on May 19, extending from Texas to South Dakota. Two violent tornadoes occurred, a EF4 tornado that directly struck Tatum, New Mexico, and a EF4 tornado that near directly struck Woodward, Oklahoma. Another very violent tornado struck near Dodge City, Kansas, and was rated a EF3, however the NWS stated that the tornado likely would've received a EF5 rating had it directly struck any structures at peak intensity. May 20 On the morning of May 20, a much more hostile atmosphere was in place, with cooler air and lower wind shear present, the Storm Prediction Center issued a slight risk of severe thunderstorms, including a 2% chance of tornadoes, or only a marginal risk. However, despite this, a series of discrete supercells impressively developed along a small and unexpected shear line, warranting a small tornado watch across portions of Missouri and Arkansas, and a upgrade to a slight risk of tornadoes with a 5% chance of tornadoes. Several significant tornadoes unexpectedly developed, including a EF3 wedge tornado near Branson, Missouri that destroyed several homes, and flattened one home, killing 1. In the end, 21 tornadoes touched down on May 20, including 2 EF3 tornadoes, one near Atkins, Arkansas and one near Branson, Missouri. May 21 By the morning of May 21, a further destabilizing atmosphere was existent across the Ohio River Valley, however with less wind shear in place and hot temperatures, and with a atmosphere more conducive for a extreme straight line wind event, the Storm Prediction Center put most of Kentucky, Illinois and Indiana under a high risk of damaging winds, with a 60% + hatched risk of damaging winds, or a maxed out potential. However, wind shear struggled to reach 2,000 J/kg across most of the area initially, which warranted the issuance of a 10% + hatched risk of tornadoes, well below high risk criteria. This was raised to a 15% + hatched risk later in the day, and much later, in the 20Z outlook, was raised to a 30% + hatched risk, or minimum high risk criteria. Despite this, the major straight line wind event never really verified until much later in the day than forecast, however a extremely significant tornado outbreak occurred instead, with 3 violent tornadoes touching down, a EF4 near North Judson, Indiana, another EF4 that tracked along a devastating path from Mulberry to Kokomo to Bluffton in Indiana, and another EF4 tornado struck Paris, Illinois. In the end, 68 tornadoes occurred on May 21, including 3 violent tornadoes, and nearly 50 people died as a result of tornadoes on May 21. It was the most prolific tornado day of 2017, and one of the deadliest and most prolific of the decade. 3 violent tornadoes touched down on May 21, one of only a few occurrences that decade in which more than 1 violent tornado touched down in a day. May 22 With the storm system approaching the end of it's life, and with a more stable atmosphere present along the Eastern Seaboard on the morning of May 22, the SPC issued a enhanced risk of mainly damaging winds, with a slight risk of tornadoes, for the Delmarva area. This event largely busted in terms of damaging winds, however a few significant tornadoes did occur, including a EF3 near Elkton, Maryland. 13 tornadoes touched down on May 22, including 1 EF3 tornado. A squall line did eventually organize, however little damaging wind reports were received, and the line was sub-severe for most of it's lifetime. Notable tornadoes Tatum, New Mexico The strongest tornado in New Mexico state history, and the second strongest tornado, as well as the first tornado of the May 19 event, this tornado touched down in the enhanced risk area at 1810. It rapidly spun up from it's EF0 strength, moving through Tatum, causing widespread EF1-EF3 damage, with one house noted to have "been shredded into dozens of large wood shards". Another house was near cleanly swept from it's foundation, warranting a EF4 rating with winds of 170 mph, making it the strongest tornado in New Mexico state history. The tornado lifted just west of the Texas state line at 1827. Lubbock, Texas The second significant tornado of the outbreak, this tornado directly struck Lubbock, Texas, just south of the moderate risk area. This tornado spun up from a long-lived discrete supercell that had previously produced the Tatum, New Mexico EF4, and had been near constantly tornado warned for over a hour on it's fast moving track. The tornado touched down at 1925, and very rapidly intensified into a EF2 tornado as it tracked to parts of Amarillo, tearing the roofs off of houses. 17 deaths were unfortunately recorded when the tornado jerked north towards a mobile home park, destroying every mobile home there, and killing 17. Dodge City, Kansas A massive wedge tornado touched down on a long-lived tornadic supercell, that had previously produced several strong tornadoes over rural areas in southwestern Kansas. The tornado initially moved over fields as a EF0 rope tornado south of Dodge City, Kansas. Multiple vortices were noted at 2244 as the tornado evolved into a cone tornado, strengthening into a EF2 tornado as it clipped multiple houses, causing minimal EF3 damage to one at 2246. The damage path width reached nearly a mile wide at spots, however it remained over very rural areas southeast of Dodge City, causing it's worst damage to a building at 2350, when a building was partially flattened, and 1 was killed. The NWS stated that a EF5 rating likely would've occurred had it been over less rural areas. Woodward, Oklahoma ''See main article here: 2017 Woodward, Oklahoma tornado The second strongest, and the widest tornado of the season touched down at 0002, on a long lived supercell with a history of producing weak (EF0-EF1) tornadoes, just west of Woodward, Oklahoma, just outside of the moderate risk area. The tornado rapidly grew, and by 0014, had caused EF2-EF3 damage to the neighborhood of Red Cedar, at a width of roughly 1.25 miles wide, it peaked in width as it neared Alston, Oklahoma, with a width of 2.2 miles, absorbing the entire town in the tornado, causing EF4 damage to every house in the town. 11 people were killed in this tornado, all of them in Alston. Branson, Missouri The strongest tornado of the May 20 event, the Branson EF3 was a relatively slow moving tornado, often moving at speeds comparable to the 1997 Jarrell, Texas tornado. However, despite this, the tornado remained over very rural areas east of Branson for most of it's life, the tornado was assigned a EF3 rating due to high-end EF3 damage to several houses, however has often been disputed for EF4 due to the fact that one well-built house was completely leveled and swept away from it's foundation, with the anchoring bolts even being slightly damaged. 1 person was killed at this residence. A small cement silo was also destroyed by the tornado, and a piece of it was rolled nearly half a mile. Atkins, Arkansas Yet another significant tornado, this tornado moved just south of the town of Atkins, Arkansas during the mid afternoon hours of May 20. Most damage produced by the tornado was of EF0-EF1 intensity, however one well-built, steel-bolted house had it's outer walls knocked down by the tornado, and was partially swept from it's foundation, resulting in 2 deaths. This was the deadliest tornado of the May 20 event, and the final significant tornado of May 20. Salem, Illinois The first significant tornado of the most prolific day of 2017, and one of the most prolific of the decade, the Salem tornado touched down shortly after 11:30 am local time on May 21, the tornado tracked in a general northeastward direction for it's lifetime, striking the community of Salem, Illinois at 1642 as a low-end EF2 tornado. However, the tornado was deadly, killing 4 people at a mobile home. A well-built house had it's roof torn off and some of the outer walls knocked down, suggesting possible EF3 intensity at one point. This tornado occurred within the high risk area, and was one of many tornadoes that day. Paris, Illinois See main article here: 2017 Paris, Illinois tornado One of the most violent tornadoes of the year, and on record despite only causing high-end EF4 damage, the Paris tornado touched down at 1958, deep within the high risk area. The tornado moved northeast over fields, and quickly intensified, striking a few houses at 2003 as a low-end EF3 tornado. From here, it likely underwent rapid intensification, with a Doppler on Wheels finding a very severe wind gust of 273.6 mph as it moved over a field. It moved into Paris at 2007 as a high-end EF4 tornado, sweeping nearly 30 houses from their foundations. One well-built house was completely swept away, with some debris found nearly 500 feet from the property, plumbing to this house was also torn out by the tornado, and this house was assigned a possible EF5 damage indicator. The tornado moved northeast, lifting at 2017 after killing 28 people. Bloomington, Indiana See main article here: 2017 Bloomington, Indiana tornado Another significant and deadly tornado, this one touched down at 2025 just south of the IU Health Bloomington Hospital, over the hospital's employee parking, the tornado tracked northeast, causing mostly EF0-EF1 damage to buildings in it's very early life. However, at 2027, as the tornado approached a Kroger, it explosively intensified into a EF3 large cone tornado, causing high-end EF3 damage to the Kroger store. A post office just across the street was swept from it's foundation, suggesting possible EF4 intensity. The tornado caused EF3 damage to hundreds of houses, as well as the IU Auditorium, which had been evacuated minutes prior. The tornado directly struck Indiana University Bloomington's campus at 2030 as a mid-range EF3, killing 2 students and a single professor, before rapidly weakening and lifting just 7 minutes later. 3 people were killed and nearly $2.5 billion in damages were inflicted in the costliest tornado in US history. Mulberry-Kokomo-Bluffton, Indiana See main article here: 2017 Mulberry-Kokomo-Bluffton, Indiana tornado '''THIS IS A WORK-IN PROGRESS!